Review of Electricity Distribution Codes and PV Connection Codes

2021 ◽  
Vol 2 (4) ◽  
Keyword(s):  
Global Economy ◽  
Reactive Power ◽  
Energy Resource ◽  
Detailed Comparison ◽  
Electricity Distribution ◽  
Control Power ◽  
Grid Connection ◽  
Technical Requirements ◽  
Fault Ride Through ◽  
Power Factor Control

Electricity is the key driver of the global economy. It is the prime energy resource for supplying customers (industry, irrigation, commerce, service, residence, etc.). This paper discusses technical requirements for Electricity Distribution Codes in various countries. The major similarities and differences between Electricity Distribution codes are clarified. Then, a detailed comparison of photovoltaic systems grid connection codes is presented. The comparison includes voltage and frequency deviations, active and reactive power control, power factor control and fault ride through.

Simulated Onshore-Fault Ride through of Offshore Wind Farms Connected through VSC HVDC

2008 ◽  
Vol 32 (2) ◽  
pp. 103-113 ◽  
Author(s):  
A. Arulampalam ◽  
G. Ramtharan ◽  
N. Caliao ◽  
J.B. Ekanayake ◽  
N. Jenkins
Keyword(s):  
Wind Farm ◽  
Reactive Power ◽  
Wind Farms ◽  
Offshore Wind ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Offshore Wind Farm ◽  
Offshore Wind Farms ◽  
Grid Connection ◽  
Fault Ride Through

Effective Onshore-Fault Ride Through was demonstrated by simulation for a Fixed Speed Induction Generator (FSIG) offshore wind farm connected through a Voltage Source Converter HVDC link. When a terrestrial grid fault occurs, power through the onshore converter reduces and the DC link voltage increases. A control system was then used to block the offshore converter. The offshore AC network voltage was reduced to achieve rapid power rejection. Reactive power at the onshore converter was controlled to support the AC network voltage according to the GB Grid Code requirements. Two cases, a 200 ms terrestrial fault and a 50% retained voltage fault of duration 710 ms, at the grid connection point were studied. The simulation results show that power blocking at the offshore converter was effective and the DC link voltage was controlled.

Research of Brushless Doubly-Fed Generator for Grid-Connection and Power Control

2014 ◽  
Vol 678 ◽  
pp. 417-422
Author(s):  
Yu Liu ◽  
Zhong Chao Wei ◽  
Xin Mai Gao ◽  
Xi Chen ◽  
Xue Fan Wang ◽  
...  
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Electrical Machine ◽  
Voltage Control Strategy ◽  
Grid Connection ◽  
Active And Reactive Power ◽  
Machine Theory ◽  
Doubly Fed ◽  
Doubly Fed Generator ◽  
Doubly Fed Machine

To reliably realize the grid-connection generating of brushless doubly-fed machine (BDFM), this paper firstly focuses on some essential issues, such as amplitude, frequency and phase of power winding voltage; the control of active and reactive power. Deducing the control method of power winding voltage amplitude, frequency and phase based on basic electrical machine principle. Referring synchronous machine theory, the modulation principle of active and reactive power for BDFM is obtained. Then, the connection progress to grid is researched by setting up the control platform based on DSP. The experimental results show that the amplitude, frequency and phase of power winding voltage are effectively controlled and the active and reactive power could be regulated when adopting the decoupled voltage control strategy. This control method provides a practical realization manner in the application of wind power generation and so on.

scholarly journals The Lead–Lag Relationship between Oil Futures and Spot Prices—A Literature Review

2018 ◽  
Vol 6 (4) ◽  
pp. 89 ◽  
Author(s):  
Miroslava Zavadska ◽  
Lucía Morales ◽  
Joseph Coughlan
Keyword(s):  
Literature Review ◽  
Crude Oil ◽  
Financial Crises ◽  
Global Economy ◽  
Dominant Role ◽  
Energy Resource ◽  
Market Uncertainty ◽  
Crude Oil Price ◽  
Oil Futures ◽  
Spot Prices

Crude oil is the dominant energy resource worldwide. The focus of this paper is on its historical behaviour and subsequent implications for the global economy with an emphasis on the lead–lag relationship between spot and future prices. The paper examines the behaviour of oil spot and future prices and their determinants during periods of market uncertainty, particularly in the context of economic and financial crises. The analysis highlights a key controversy within the extant literature, as to whether spot or futures prices are the main crude oil price indicator. The literature review indicates that the lead–lag relationship is a dynamic one, especially during periods of sustained uncertainty, which leads to significant disagreements and incongruities among researchers regarding the price that plays a dominant role.

scholarly journals Identifying Potential Landslides by Stacking-InSAR in Southwestern China and Its Performance Comparison with SBAS-InSAR

2021 ◽  
Vol 13 (18) ◽  
pp. 3662
Author(s):  
Lele Zhang ◽  
Keren Dai ◽  
Jin Deng ◽  
Daqing Ge ◽  
Rubing Liang ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Detailed Comparison ◽  
Performance Comparison ◽  
Small Displacement ◽  
Mountainous Areas ◽  
Technical Requirements ◽  
Local Residents ◽  
Time Series Method ◽  
Sbas Insar ◽  
High Consistency

Landslide disasters occur frequently in the mountainous areas in southwest China, which pose serious threats to the local residents. Interferometry Synthetic Aperture Radar (InSAR) provides us the ability to identify active slopes as potential landslides in vast mountainous areas, to help prevent and mitigate the disasters. Quickly and accurately identifying potential landslides based on massive SAR data is of great significance. Taking the national highway near Wenchuan County, China, as study area, this paper used a Stacking-InSAR method to quickly and qualitatively identify potential landslides based on a total of 40 Sentinel SAR images acquired from November 2017 to March 2019. As a result, 72 active slopes were successfully detected as potential landslides. By comparing the results from Stacking-InSAR with the results from the traditional SBAS-InSAR (Small Baselines Subset) time series method, it was found that the two methods had a high consistency, with 81.7% potential landslides identified by both of the two methods. A detailed comparison on the detection differences was performed, revealing that Stacking-InSAR, compared to SBAS-InSAR may miss a few active slopes with small spatial scales, small displacement levels and the ones affected by the atmosphere, while it has good performance on poor-coherence regions, with the advantages of low technical requirements and low computation labor. The Stacking-InSAR method would be a fast and powerful method to qualitatively and effectively identify potential landslides in vast mountainous areas, with a comprehensive understanding of its specialty and limitations.

A New Robust H∞ Control Power

2017 ◽  
pp. 1695-1718
Author(s):  
Samir Abdelmalek ◽  
Hocine Belmili
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Controller Design ◽  
Pi Controller ◽  
Control Technique ◽  
Wind Energy Conversion Systems ◽  
Grid Connection ◽  
Energy Conversion Systems ◽  
Sensitivity Problem ◽  
Doubly Fed

Attention has been paid by many researchers to address the various challenges of grid connection of DFIG-based Wind Energy Conversion Systems (WECS). This chapter focuses on the design of a robust H8 controller for the power flow between the stator of the Doubly-Fed Induction Generator (DFIG) and the grid. The robust H8 controller design is formulated as a mixed-sensitivity problem. A mathematical model of the DFIG written in an appropriate d-q reference frame is established to carry out simulations. The proposed power control scheme is elaborated and compared with a conventional Proportional-Integral (PI) controller based on vector control technique. The results show interesting performance of the controlled system in terms of the power reference tracking (the active and reactive power) and robustness against parameter variations compared with the conventional PI controller.

scholarly journals Fault Ride through Capability Augmentation of a DFIG-Based Wind Integrated VSC-HVDC System with Non-Superconducting Fault Current Limiter

2019 ◽  
Vol 11 (5) ◽  
pp. 1232 ◽  
Author(s):  
Md Alam ◽  
Mohammad Abido ◽  
Alaa Hussein ◽  
Ibrahim El-Amin
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Current Control ◽  
Control Mode ◽  
Voltage Source ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Hvdc System ◽  
Fault Ride Through ◽  
Current Limiter

This paper proposes a non-superconducting bridge-type fault current limiter (BFCL) as a potential solution to the fault problems of doubly fed induction generator (DFIG) integrated voltage source converter high-voltage DC (VSC-HVDC) transmission systems. As the VSC-HVDC and DFIG systems are vulnerable to AC/DC faults, a BFCL controller is developed to insert sizeable impedance during the inception of system disturbances. In the proposed control scheme, constant capacitor voltage is maintained by the stator VSC (SVSC) controller, while current extraction or injection is achieved by rotor VSC (RVSC) controller. Current control mode-based active and reactive power controllers for an HVDC system are developed. Balanced and different unbalanced faults are applied in the system to show the effectiveness of the proposed BFCL solution. A DFIG wind-based VSC-HVDC system, BFCL, and their controllers are implemented in a real time digital simulator (RTDS). The performance of the proposed BFCL control strategy in DFIG-based VSC-HVDC system is compared with a series dynamic braking resistor (SDBR). Comparative RTDS implementation results show that the proposed BFCL control strategy is very efficient in improving system fault ride through (FRT) capability and outperforms SDBR in all cases considered.

Grid Connection Control of DFIG Wind Power Generation

2013 ◽  
Vol 373-375 ◽  
pp. 1287-1293
Author(s):  
Jian Wei Liang ◽  
Tao Wang
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Basic Structure ◽  
Grid Connection ◽  
Stator Flux ◽  
Set Up ◽  
Grid Side ◽  
Rotor Side Converter ◽  
Stator Flux Oriented ◽  
And Control

The paper is based on PSCAD/EMTDC. The basic structure and operation principle of DFIG are analyzed and the mathematical model of DFIG is established, based on which the control system of rotor-side and grid-side converters is set up. The stator flux-oriented vector control is adopted for rotor-side converter. The no-load grid connection is realized before cutting in and control strategy is switched after grid connection successfully. DFIG can meet grid connection condition quickly with the control strategy and is connected to grid with no current shock nearly. The output of active and reactive power can be regulated respectively.

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